Method and apparatus for cutting a ribbon of rubber-coated fabric

ABSTRACT

A method for cutting a ribbon of rubber-coated fabric includes dragging a free end of the ribbon past a working position of a punching device, forming a notch between two adjacent reinforcing cords of the ribbon using the punching device, moving a counter-blade of the punching device away from the working position, inserting at least one cutting blade through the notch, and performing first and second cuts of the ribbon. An associated apparatus includes a punching device and a cutting device. The punching device includes an incision tool, an abutting counter-blade, and control devices for moving the incision tool and the abutting counter-blade toward and away from the ribbon. The cutting device includes at least one cutting blade and a control device for moving the at least one cutting blade toward and away from the ribbon.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a national-phase entry under 35 U.S.C. § 371 fromInternational Application No. PCT/IB01/02025, filed Oct. 25, 2001, inthe International Bureau of the World Intellectual PropertyOrganization, the content of which is relied upon and incorporatedherein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

In a first aspect thereof, the present invention relates to a method forcutting a ribbon of rubber-coated fabric including a plurality ofreinforcing cords substantially parallel to one another, such as forinstance a belt strip or other semi-finished reinforcing productsintended for manufacturing the carcass of a green tire for vehicles.

In the following description and in the subsequent claims, the term:“ribbon of rubber-coated fabric”, is used to indicate any continuousstrip of rubber mixture embedding a plurality of reinforcing cords, byway of example metal and/or textile cords substantially parallel to oneanother.

The present invention also relates to an apparatus for cutting a ribbonof rubber-coated fabric including a plurality of reinforcing cords asdefined above.

2. Description of the Related Art

As is known, a green tire is essentially constituted by a compositestructure obtained by assembling together a plurality of semi-finishedproducts and comprising: an airproof liner; at least one reinforcingply; two bead cores to which the ply edges are associated; anelastomeric filling fixed to the radially outer surface of each beadcore; a belt structure arranged as a crown around the torically shapedcarcass ply generally comprising at least one pair of radiallysuperposed belt strips provided with reinforcing cords crossed with eachother and inclined with respect to the circumferential direction of thetire; a tread band wrapped around the belt structure; and a pair ofaxially opposite sidewalls radially extending between the bead cores andthe tread band. The belt structure may also comprise a further layergenerally arranged at the radially outermost position, incorporating aplurality of circumferentially oriented reinforcing cords, otherwiseknown as zero degree cords.

In order to manufacture semi-finished reinforcing products, such as forexample the belt strips intended for forming the above-mentioned beltstructure, a ribbon of rubber-coated fabric is generally utilized, saidribbon including a plurality of reinforcing cords substantially parallelto one another and inclined of a predetermined angle with respect to acentral longitudinal plane of the ribbon (said angle being typicallycomprised between about 15° and 30°), which ribbon is cut to sizeaccording to a cutting direction as parallel as possible to thedirection of the reinforcing cords in order to minimize the risk ofcutting or damaging one or more cords. The damaged reinforcing cords, infact, and particularly those emerging from the ribbon in which they areincorporated (know in the art with the term of “wild wires”), cause notonly the generation of a semi-finished product of unacceptable quality,but may also cause the jamming of the automatic machines utilized formanufacturing the green tires, with a consequent need of laborintervention and an increase in production costs. Besides, if animprecise cutting of the ribbon of rubber-coated fabric should cause acomplete breaking of the reinforcing cords (such as for example thebreaking of one or more threadlike elements of the cord and/or one ormore strands of the cord) or a divarication of the free end of a cord(known in the art with the term of “splayed point cord”), the furtherrisk of a defect difficult to be detected by means of a conventionalquality control of the tire arises, so that the defect can becomevisible only in operation, leading even to a precocious and dangerousdamages of the tire structure.

In view of above, one of the objects of the art of the field is that ofpreventing an imperfect cutting of the ribbon of rubber-coated fabricfrom negatively affecting both the tire quality and the productivity ofthe plants for manufacturing green tires.

To this purpose, for example, cutting apparatuses provided essentiallywith a blade intended, in a first step, for penetrating the rubberbetween two adjacent cords, approximately in the middle of the ribbon ofrubber-coated fabric, are used, forming in this manner a through-notchof predetermined length and, in a second step, for cutting the ribbon ofrubber-coated fabric from one side to the other, starting from theabove-mentioned notch. In some cases, said steps of penetration (i.e. ofincision) within the rubber of the fabric and of cutting are carriedout, respectively, by two blades instead of one.

For instance, patents U.S. Pat. No. 2,665,757 and U.S. Pat. No.3,641,855 describe a cutting apparatus essentially constituted by a pairof identical blades movable along a direction parallel to the cords,each one of which provided with a sharpened portion adapted to penetratethe ribbon of fabric, and provided with a blunt portion to tear therubber of the ribbon present between adjacent cords. On the basis of thecutting methods of the ribbon of rubber-coated fabric illustratedtherein, the blades, by means of their sharpened portion, make astarting notch in the ribbon and, subsequently, by moving in oppositedirections starting from the above-mentioned starting notch, completesaid cutting while theoretically remaining between two adjacent cords.

The cutting methods and apparatuses described in the above documents,however, imply the non negligible risk of damaging or cutting thereinforcing cords, generating thereby the so-called “wild wires” duringthe starting incision step of the ribbon of rubber-coated fabric by thesharpened portions of the blades.

Besides, the cutting apparatus described in document U.S. Pat. No.2,665,757 comprises two presser feet intended for holding in a fixedposition the ribbon portion positioned astride the cutting zone, inorder to facilitate the cutting operations.

However, in this manner, because of the rigid constraint to which saidribbon is subjected during the cutting operation, it has been found thatthe cords may be passed over and irreversibly damaged by the blade whenthe cords have—because of stretches or strains undergone by the ribbonduring the preceding working and handling steps to which the ribbon issubmitted—a different inclination with respect to the nominalinclination, on the basis of which the cutting direction is set.

A further similar cutting apparatus, showing the same drawbacksillustrated above, is described in patent U.S. Pat. No. 4,608,890. Saidapparatus comprises only one blade performing a starting notch of theribbon of rubber-coated fabric and completing the cut starting from saidstarting notch by means of a stroke extending between the oppositelateral edges of the ribbon.

Further cutting methods and apparatuses, described for instance inpatents U.S. Pat. No. 4,156,378 and U.S. Pat. No. 4,210,042, employ acircular blunt blade or a pair of circular blunt blades able to engage,by a rotating motion, the ribbon of rubber-coated fabric and to cut thesame between a pair of adjacent cords. Also in this case, it has beenfound that the cords may be easily passed over and irreversibly damagedby the circular blade rotating and translating when the cords have adifferent inclination with respect to the nominal inclination.

The above-mentioned drawbacks, not negligible even per se, are furtheramplified both when the cords have a reduced diameter (by way of examplesmaller than about 0.4-0.7 mm) and as the width of the ribbon ofrubber-coated fabric to be submitted to the cutting operation increases(by way of example greater than about 350 mm) because of the followingreasons.

Firstly, a trend to progressively reduce the diameter of the reinforcingcords has been spreading, which trend is mainly dictated by the attemptof reducing the moment of inertia of the tire and the overall weight ofthe same. Said trend increases the risk of cutting or damaging thecords, if markedly pointed or sharpened portions of the blades areutilized, as stressed above with reference to patents U.S. Pat. No2,865,757, U.S. Pat. No. 3,641,855 and U.S. Pat. No. 4,608,890. At thesame time, said trend necessarily implies the requirement of increasingthe density of the reinforcing cords in order to ensure the samemechanical strength which would be obtained by using cords havinggreater diameters and, with this requirement, the increased risk ofdamaging or even cutting a cord during the starting incision step of theribbon of rubber-coated fabric.

Secondly, the trend of employing tires having a footprint area alwaysincreasing, necessarily results in an increase of the width of thesemi-finished products of rubber-coated fabric such as, for example, thebelt strips. Said increase of the width necessarily causes the increaseof the cutting path and, therefore, the likelihood of impairing thequality of the semi-finished product due to a cut made in an incorrectmanner.

In addition to this trend and associated thereto, in order to increasethe performance of the tire, the necessity of reducing the inclinationangle of the reinforcing cords with respect to the central longitudinalaxis has arisen. Hence, the necessity of performing a precise cut interms of holding a cutting direction as constant as possible throughoutthe whole cutting path of the ribbon of rubber-coated fabric.

On the other hand, even if it were possible to ensure a substantiallyconstant cutting direction throughout the whole cutting path of theribbon of rubber-coated fabric, the risk of passing over and damagingone or more cords persists because of the risk of stretches or strainsof the fabric in the preceding working steps, which risk is particularlyhigh during the storage on a reel of the ribbon of rubber-coated fabricor in any case during the other handling operations of the same. Saidstretches or strains of the ribbon of rubber-coated fabric, which areresponsible for the deviation of the inclination of the reinforcingcords with respect to the nominal inclination, contribute to thedifficulty of cutting a ribbon of rubber-coated fabric in a precise andrepeatable manner without damaging the reinforcing cords thereof.

SUMMARY OF THE INVENTION

The Applicant has found that it is possible to overcome the drawbacks ofthe known art by performing the cutting operations by means of a cuttingapparatus comprising: a punching device comprising an incision toolsuitable for incising the ribbon within the space comprised between twoadjacent cords along a cutting direction substantially parallel to thecords, and an abutting counter-blade cooperating with the incision tool;and a cutting device comprising at least a cutting blade movable alongsaid cutting direction.

According to a first aspect thereof, the present invention relatestherefore to a method for cutting a ribbon of rubber-coated fabricincluding a plurality of reinforcing cords substantially parallel to oneanother, said method comprising the steps of:

-   -   a) dragging a free end of said ribbon for a portion of        predetermined length past a working position of a punching        device;    -   b) forming between two adjacent cords by means of said punching        device a notch of predetermined length extending along a cutting        direction substantially parallel to said cords;    -   c) moving the counter-blade of the punching device away from        said working position;    -   d) inserting at least one cutting blade through said notch, said        at least one blade passing over the lying plane of said ribbon;    -   e) performing a first cut of said ribbon by shifting said blade        along said cutting direction for a first portion extending        between said notch and a first lateral edge of said ribbon; and    -   f) performing a second cut of said ribbon by shifting said blade        along said cutting direction for a second portion extending        between said notch and an opposite lateral edge of said ribbon.

Thanks to the fact that the punching device has an incision toolcooperating with the abutting counter-blade, said incision toolmaintains its own insertion position between adjacent cords, so that itbecomes advantageously possible to perform a notch between two adjacentreinforcing cords which affects only the rubber portion lying betweenthe cords, minimizing the risk of intersecting said cords, andminimizing therefore both the amount of production scraps and the riskof jamming the automatic manufacturing machines.

Preferably, step b) of forming the notch is carried out by holding theribbon upstream and downstream of the cutting direction at a distancesuch as to allow freedom of shifting, in a direction parallel to thelying plane of the ribbon, to the ribbon portion located at theabove-mentioned working position of the incision tool of the punchingdevice, i.e. at a position astride the cutting direction.

Advantageously, said freedom of shifting of said ribbon portion allows,during the incision operation, a corresponding shifting of said portionwith respect to the incision tool against the lateral surface of whichthe reinforcing cords can possibly abut without however being cut orpassed over by the incision tool if the inclination of said cords shoulddeviate from the nominal inclination.

Preferably, also the first and the second cutting steps e), f) arecarried out by holding the ribbon upstream and downstream of the cuttingdirection at a distance such as to allow a freedom of shifting, in adirection parallel to the lying plane of the ribbon, of said ribbonportion located astride the cutting direction.

Similarly to above, the reinforcing cords incorporated in the ribbon ofrubber-coated fabric and adjacent to the cutting blade canadvantageously freely shift with respect to the blade along the lyingplane of the ribbon, reducing substantially to zero the risk of damagingthe cords during the cutting steps.

In fact, in case of deviations of the inclination of the reinforcingcords with respect to the nominal inclination and thanks to the factthat the cutting blade is inserted into the notch so as to pass over thelying plane of the ribbon, the cords adjacent to the cutting blade abutagainst the lateral walls of the latter, eliminating the risk of beingdamaged by the blade cutting edges.

Hence, in this preferred embodiment, the reinforcing cords are notdamaged neither during step b) of forming the notch, nor during steps e)and f) of cutting the ribbon, since said cords can follow the movementsof the incision tool and, respectively, of the cutting blade, freelyfloating on the lying plane of the ribbon, so that the incision tool andthe cutting blade engage only the rubber portions interposed between twoadjacent cords.

Preferably, the notch obtained by the punching device in theabove-mentioned step b) has a depth comprised between 80% and 90% of theoverall thickness of the ribbon of rubber-coated fabric, such as tofacilitate the insertion of the cutting blade into said notch, asprovided by step d) of the method of the invention. Even morepreferably, the notch formed by the punching device in theabove-mentioned step b) is a through-notch, so as to further facilitatethe insertion of the cutting blade into the notch.

Preferably, said step b) of forming the notch is carried out by arotation-translational movement of the incision tool. Said preferredcharacteristic of the method, together with the fact that the ribbon ofrubber-coated fabric can freely shift along its own lying plane,advantageously allows to prevent the undesired passing over of thereinforcing cords by the incision tool when the inclination of the cordsis different from their nominal inclination, in a direction parallel towhich the shifting direction (and therefore the incision direction) ofthe incision tool is set.

Preferably, the punching device is translated along the cuttingdirection for a stroke comprised between about 60 and about 100 mm and,even more preferably, between about 70 and about 90 mm.

Preferably, said steps c) and d) are carried out simultaneously,advantageously reducing thereby the working time.

According to a preferred embodiment, also the above-mentioned steps e)and f) may be carried out simultaneously by using a pair of cuttingblades movable along the cutting direction but in an opposite directionwith respect to each other, with a further advantageous reduction inworking time.

Preferably, said cutting steps e) and f) are carried out by imparting tothe cutting blade a translational speed comprised between about 1 m/minand about 15 m/min, more preferably between about 5 m/min and about 10m/min.

According to a preferred embodiment thereof, the method of the inventionfurther comprises the step of moving the incision tool of the punchingdevice away from said working position before the step d) of insertingsaid at least one cutting blade through the notch formed in the ribbon.

In this manner, the insertion of said at least one cutting blade throughthe notch is advantageously further facilitated.

Preferably, the notch is formed astride the central longitudinal planeof the ribbon. In this manner, as first portion of the ribbon ofrubber-coated fabric to be cut is selected that one involving theminimum risk of damaging the cords since said portion, being far fromthe lateral edges of said ribbon, is less sensitive to possible strainswhich might cause a deviation of the inclination of the reinforcingcords with respect to the nominal inclination.

According to a further preferred embodiment of the invention, the firstcutting step e) is carried out by holding the cutting blade within theopposite lateral edges of the ribbon of rubber-coated fabric, i.e.preventing the cutting blade from coming out entirely from the lateraledges of the rubber-coated fabric. In this manner, at the end of thefirst cutting step e) and before carrying out the second cutting stepf), the cutting blade needs not to be positioned again in the spacebetween the cords where the first cut has been made, since said bladehas not been entirely removed from said fabric, remaining at leastpartly in touch with the latter.

Preferably, the method of the invention further comprises the step ofheating to a given temperature said at least one cutting blade. In thismanner, the cutting of the ribbon of rubber-coated fabric between twoadjacent reinforcing cords is advantageously facilitated.

Preferably, said temperature is comprised between about 100° C. andabout 140° C. and, even more preferably, between about 110° C. and about130° C.

According to a second aspect thereof, the present invention relates toan apparatus for cutting a ribbon of rubber-coated fabric including aplurality of reinforcing cords substantially parallel to one another,said cutting apparatus comprising:

-   -   a) a punching device comprising:        -   a1) an incision tool suitable for incising said ribbon            between two adjacent cords along a cutting direction            substantially parallel to said cords;        -   a2) an abutting counter-blade, said incision tool            cooperating with said abutting counter-blade at a working            position of the punching device; and        -   a3) respective control devices for moving the incision tool            and the abutting counter-blade towards and away from said            ribbon; and    -   b) a cutting device comprising:        -   b1) at least one cutting blade movable along said cutting            direction for cutting said ribbon along said direction and            in a direction substantially parallel to said cords; and        -   b2) a control device for moving said at least one cutting            blade towards and away from said ribbon.

Advantageously, the presence of the punching device and of the abuttingcounter-blade cooperating with the same allows the apparatus of theinvention to perform an incision of the ribbon of rubber-coated fabricsuch as to minimize the risk of intersecting the reinforcing cords.

Preferably, the cutting apparatus of the invention further comprises arotation device intended for aligning along the desired cuttingdirection—in a preliminary step of the method of the invention—theincision tool and, respectively, the abutting counter-blade cooperatingwith the same and the cutting blade.

According to a preferred embodiment of the apparatus of the invention,said incision tool comprises a punching disc provided with a roundedperipheral edge. Preferably, said punching disc is pivotally supportedby the punching device.

Preferably, the punching disc has a diameter comprised between about 30mm and about 60 mm and, even more preferably, between about 40 mm andabout 50 mm.

In a preferred embodiment thereof, the punching device further comprisesa handling device for shifting said incision tool along the cuttingdirection.

Thanks to the fact that the punching disc performs a movement ofrotation-translational type, the risk of damaging the cords isadvantageously minimized, enabling the latter to abut against theopposite lateral faces of the disc and carrying out a correct punchingjust of the rubber portion interposed between two adjacent cords of theribbon of rubber-coated fabric.

Preferably, said at least one cutting blade comprises a blade bodylaterally provided with at least one recess provided with a respectivecutting edge.

Preferably, said blade body is laterally provided, on axially oppositeparts, with a pair of recesses provided with a respective cutting edge.The presence of two opposite cutting edges in the blade bodyadvantageously allows to have only one blade able to cut the ribbon ofrubber-coated fabric in both directions along the cutting direction,i.e. from the notch towards the first lateral edge of said ribbon andfrom the notch towards the second lateral edge of said ribbon,maintaining always the same orientation of the blade body. Saidpreferred embodiment is particularly suitable when the apparatuscomprises only one cutting blade.

According to a preferred embodiment, the cutting device furthercomprises a handling device for shifting said cutting blade along thecutting direction.

Preferably, the punching device and the cutting device are fixed to asame supporting trolley movable along the cutting direction, saidtrolley constituting an unique handling device along the cuttingdirection both of the punching device and of the cutting device.

Preferably, the cutting device of the invention further comprises adragging device for dragging a free end of the ribbon for a portion ofpredetermined length past the working position of the punching device.Preferably, said portion corresponds to the length of the strip (orportion) of the reinforcing rubber-coated fabric to be used in themanufacture of the green tire.

In this manner, it is advantageously possible to cut to size the ribbonof rubber-coated fabric into a plurality of portions of predeterminedlength.

According to a further preferred embodiment, said dragging device of theribbon comprises a plate movable between a first position upstream ofthe working position of the punching device and a second positionlocated downstream of the working position of the punching device ofsaid portion of predetermined length.

Preferably, the cutting apparatus further comprises a device forsupporting said ribbon, while maintaining the same at a predetermineddistance from the cutting line of the cutting blade, so that the ribbonedges adjacent to the cutting blade can be freely shifted.

Lastly, in a preferred embodiment, the cutting apparatus furthercomprises a heating device for heating said at least one cutting bladeto a given temperature, so as to further facilitate the cuttingoperations of the ribbon of rubber-coated fabric.

BRIEF DESCRIPTION OF THE DRAWINGS

Additional features and advantages of the invention will be more readilyapparent from the description of some embodiments of a method forcutting a ribbon of rubber-coated fabric according to the invention,made with reference to the attached drawings in which, for illustrativeand non limiting purposes, a preferred embodiment of a cutting apparatusfor carrying out said method is shown.

In the drawings:

FIG. 1 is a perspective view of a preferred embodiment of a cuttingapparatus according to the invention;

FIG. 2 is a lateral elevational view of the cutting apparatus of FIG. 1;

FIGS. 3, 5, 7 and 9 are schematic elevational views of some details ofthe cutting apparatus of FIG. 1, in different operative conditions ofthe same;

FIGS. 4, 6, 8 and 10 are partial schematic top views of a ribbon ofrubber-coated fabric in different operative conditions of the apparatusof FIG. 1.

FIG. 11 is a partial schematic top view of a ribbon of rubber-coatedfabric in an operative condition of another cutting apparatus accordingto the invention in which the apparatus of FIG. 1 has been modified toprovide a pair of cutting blades.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to FIGS. 1 and 2, a cutting apparatus according to thepresent invention for cutting a ribbon 2 of rubber-coated fabricincluding a plurality of reinforcing cords 3, for example of metal,substantially parallel to one another, is generally indicated withreference sign 1. For illustrative purpose, the cords 3 (as shown betterin FIG. 4) are inclined of a predetermined angle α with respect to acentral longitudinal plane Π-Π of the ribbon 2. Said angle α is forexample comprised between about 5° and about 175°, said range includingthe inclination of the reinforcing cords generally provided in a pair ofbelt strips radially superposed to each other, the cords of each stripbeing crossed with respect to those of the radially adjacent strip andinclined with respect to the circumferential direction of the tire.

In FIG. 1, the ribbon 2 of rubber-coated fabric to be cut into aplurality of portions of predetermined length, for example intended forconstituting a plurality of belt strips, is at a position U upstream ofthe apparatus 1. At said position U, the ribbon 2 is supported by aplurality of rolls 21 or other suitable devices known in the art, suchas conveyor belts, mobile tables, etc., suitable for conveying theribbon 2 of rubber-coated fabric from a production or storing device ofthe ribbon, for example a collection reel (not shown), towards thecutting apparatus 1.

According to the invention, the cutting apparatus 1 comprises a punchingdevice 4 and a cutting device 5.

More particularly, the punching device 4 comprises an incision tool 6suitable for incising the ribbon 2 between two adjacent cords 3 along acutting direction C-C substantially parallel to the cords 3 (see FIG.4), an abutting counter-blade 7, a control device 36 for moving theincision tool 6 towards and away from said ribbon 2 of rubber-coatedfabric, as well as a control device 8 for moving the abuttingcounter-blade 7 towards and away from said ribbon 2 of rubber-coatedfabric.

According to the preferred embodiment shown, the incision tool 6comprises a punching disc 9 provided with a rounded peripheral edge 10,which disc is pivotally mounted at a free end of an arm 11 of thecontrol device 36 of the punching disc 9.

The arm 11, in its turn, is hinged, at the other free end thereof, to atrolley 13, better illustrated below.

The incision tool 6 cooperates with the abutting counter-blade 7 at aworking position W of the punching device 4. The vertical translation ofthe counter-blade 7, preferably made of stellite or any other materialof suitable hardness, is controlled by the already mentioned controldevice 8.

According to the invention, the cutting device 5 comprises at least onecutting blade 19 movable along the cutting direction C-C for cutting theribbon 2 along this direction and in a direction substantially parallelto the cords 3, and a control device 37 for moving the cutting bladetowards and away from the ribbon 2 of rubber-coated fabric.

The blade 19 of the cutting device 5 comprises at least one recessprovided with a respective cutting edge. According to the preferredembodiment shown in FIG. 1, the blade body is laterally provided with apair of recesses, each provided with a respective cutting edge.

Preferably, the control device 37 comprises a control arm 20 on whichthe cutting blade 19 is supported at a free end thereof. In its turn,the arm 20 is hinged, at the other free end thereof, to the trolley 13.

For illustrative purpose, the control devices 36 and 37 for moving theincision tool 6 and, respectively, the cutting blade 19 towards and awayfrom the ribbon 2 may comprise respective actuators, for example ofpneumatic type, not shown and of a conventional type, acting on theincision tool 6 and, respectively, on the cutting blade 19 by means ofthe respective control arms 11 and 20.

The control device 8, intended for moving the abutting counter-blade 7towards and away from the ribbon 2 of rubber-coated fabric, comprises,in the preferred embodiment shown, a pneumatic cylinder 23 suitable forshifting, by means of a stem 31, the counter-blade 7 in touch with and,alternatively, away of a predetermined distance from the ribbon 2, inorder to make the counter-blade 7 cooperate with the incision tool 6.Besides, said control device 8 is suitable for removing thecounter-blade 7 from the range of action of the cutting blade 10, at aposition of non-interference with the stroke of the latter.

In the embodiment shown, the pneumatic cylinder 23 acting on thecounter-blade 7 is mounted on a base 16 b fixed, in its turn, to asupporting frame 16.

According to the embodiment shown, the punching device 4 and the cuttingdevice 5 further comprise respective handling devices for shifting thepunching disc 9 and, respectively, the cutting blade 19 along thecutting direction C-C. In the preferred shown embodiment, the punchingdisc 9 and the cutting blade 19 are translated along the cuttingdirection C-C by a same handling device 12 comprising said supportingtrolley 13 movable along the cutting direction C-C. Preferably, thetrolley 13 is horizontally translated by means of a plurality of wheels14, preferably arranged in two rows parallel to each other to increasethe stability of the trolley 13, said wheels 14 sliding along a pair oftracks 29 a, 29 b suitably supported, for instance by means of a centralrod 15 b and two lateral rods 15 a, 15 c, by means of a tie-rodpivotally mounted above the trolley 13 about a rotation axis X-X of thecutting apparatus 1.

According to the preferred embodiment shown, the trolley 13 ishorizontally translated by a lead screw 17 kinematically connected to anelectric motor 18. In this way, a rotation of the lead screw 17 turnsinto a corresponding horizontal translation of the trolley 13 along thecutting direction C-C.

The central rod 15 b, preferably coaxially extended with respect to saidrotation axis X-X, is vertically translated by a suitable controldevice, such as for example a pneumatic cylinder 34, towards and awayfrom the lying plane of the ribbon 2, so that the distance of thetrolley 13 with respect to the lying plane of the ribbon 2 can beconveniently adjusted on the basis of the size of the incision tool 6and of the cutting blade 19.

In other words, the trolley 13 can be both translated towards or awayfrom the lying plane of the ribbon 2 by the pneumatic cylinder 34 androtated about the rotation axis X-X in a given angular position.

The cutting apparatus 1 may further comprise a dragging device(conventional per se and not shown) for dragging a free end of theribbon 2 for a portion of predetermined length past the working positionW of the punching device 4. Said dragging device may for instanceinclude a dragging plate, preferably provided with magnets, parallel tothe counter-blade 7 and movable between the position U upstream or theworking position W of the punching device 4 and a position D downstreamof the working position W of the punching device 4. More particularly,said dragging plate is suitable for dragging the ribbon 2 ofrubber-coated fabric away from the rolls 21 towards the punching device4 for a portion having a length equal to the length of the strip offabric to be obtained.

In alternative to the magnets, the dragging plate may be provided, withdevices suitable for holding the ribbon material, such as for example aplurality of suction cups connected to a vacuum pump, particularlysuitable when the cords 3 are made of a non-magnetic material, forexample textile fibers, glass fibers or mixed fibers.

Alternatively, the dragging device may include a pair of conveyor beltslocated at the positions U upstream and, respectively, D downstream ofthe apparatus 1, and intended for being alternatively active on theribbon 2.

According to the embodiment shown, the cutting apparatus 1 furthercomprises a device for supporting the ribbon 2 at a predetermineddistance from the cutting path performed by the cutting blade 19 whenthe counter-blade 7 is moved away from the working position W.

In the example illustrated, the device for supporting the ribbon 2comprises a sheet 30 substantially L-shaped at the upper end thereof, soas to form a lip 41 cantilevered from a central body of the sheet 30,substantially throughout the length of the same. Conveniently, the lip41 provides a bearing surface for the ribbon 2 when the counter-blade 7is moved away from the working position W.

For this purpose, the sheet 30 is laterally supported with respect tothe counter-blade 7 by the frame 16, against which the sheet 30 is heldat the opposite end with respect to lip 41 by means of a plurality ofbolts 39 positionable at will between respective slot positions 44, 45suitably shaped and obtained on an upper face 16 c of the frame 16.

Advantageously and as will be more apparent in the following, whenplaced between slot positions 44 and 45 the bolts can hold the sheet 30in the desired angular position after a rotation of said sheet about therotation axis X-X of the cutting apparatus 1.

In order to accomplish a vertical slide of the counter-blade 7, thesheet 30 comprises a plurality of slots 35 of predetermined length, inwhich a corresponding plurality of stakes 38 protruding from thecounter-blade 7 is slidingly mounted. Besides, the reciprocal distancebetween the sheet 30 and the counter-blade 7 can be advantageouslyadjusted by means of a plurality of nuts 42 engagingly screwed on athreaded end of the stakes 38.

In this way, the counter-blade 7 can also vertically translate towardsand away from the ribbon 2 of rubber-coated fabric for a stroke ofpredetermined length, substantially equal to the length of the slots 35.

According to the preferred embodiment shown, the counter-blade 7 and thesheet 30 associated thereto integrally rotate with the tie-rod 16 athrough a rod 27 fastened, on the upper end thereof, to the tie-rod 16 aand cooperating with an arm 33 fastened to the counter-blade 7.

A rotation of the tie-rod 16 a about the axis X-X turns therefore into acorresponding rotation of the trolley 13 and, thanks to the presence ofthe rod 27 and of the arm 33 connected thereto, of the counter-blade 7and of the sheet 30.

Conveniently, a shank 40 of predetermined length extends from the lowerend of the rod 27 and is received, thanks to the mating shapes of thesame, in a corresponding hole obtained at the free end of the arm 33.

In this way, the arm 33 can slide with respect to the rod 27 each timethe counter-blade 7 is vertically driven by the pneumatic cylinder 23.

According to the embodiment shown, the cutting apparatus 1 furthercomprises a blocking device, schematically indicated at 22 in FIG. 1,including for instance two jaws 22 a, 22 b, one of which is fastened tothe wall 28 by means of a fastening arm 32, which jaws are suitable forbeing tightened around the central rod 15 b. The blocking device 22,closed for instance by means of suitable tightening screws, not shown,will hold the trolley 13, the counter-blade 7 and the sheet 30 in thedesired angular position with respect to the ribbon 2, so that theincision tool 6, the abutting counter-blade 7 cooperating with the same,the cutting blade 19 and sheet 30 are all aligned along theabove-mentioned cutting direction C-C.

Thanks to the presence of said blocking device 22, it is advantageouslypossible to feed the ribbon 2 of rubber-coated fabric to the apparatus 1through the rolls 21 without changing the feed direction imparted to theribbon 2 by the rolls 21 in case of variation of the inclination of thereinforcing cords 3, but simply rotating the cutting apparatus 1 so asto align the cutting direction C-C with the new inclination of the cords3.

The cutting apparatus 1 may further include a heating device,conventional per se and not shown, for heating the cutting blade 19 to agiven temperature.

With reference to the above-mentioned apparatus, the method according tothe invention for cutting a ribbon 2 of rubber-coated fabric, forexample for cutting said ribbon into a plurality of strips ofpredetermined length, includes in a preferred embodiment thereof thefollowing steps.

The ribbon 2, coming for example from a collection reel, is positionedon the rolls 21 in order to be fed to the cutting apparatus 1. Should itbe necessary, for example upon a change of the product specifications,the tie-rod 16 a and, together with the same, the trolley 13, thecounter-blade 7 and the sheet 30, are rotated about the axis X-X in thedesired angular position and held therein by means of the blockingdevice 22.

Conveniently, the bolts 39 holding the sheet 30 slide during saidrotation between slot positions 44 and 45 having the purpose of enablingthe desired rotation with respect to the upper face 16 c of the frame16.

At the end of said possible rotation, the sheet 30 is held at the newangular position with respect to the upper face 16 c of the frame 16through the bolts 39.

In this way, the incision tool 6, the cutting blade 19, thecounter-blade 7 and the sheet 30 are aligned according to thepredetermined cutting direction C-C, parallel to the direction of thereinforcing cords 3 of the ribbon 2.

In a first step of the method, a free end of the ribbon 2 is dragged bythe dragging device—not shown—for a portion of predetermined length(indicated at 1 in FIG. 3) past the working position W of the punchingdevice 4. Besides, in this step of the method, the counter-blade 7 isvertically translated, in the case in point lifted, by the stem 31 ofthe pneumatic cylinder 23 in contact with the ribbon 2 of rubber-coatedfabric, to the working position W.

In a second step of the method of the invention, as shown in FIG. 4, anotch 24 having a predetermined length n extending along the cuttingdirection C-C is formed between two adjacent cords 3 of the ribbon 2.

This takes place by means of a rotation-translation of the punching disc9 driven towards the ribbon 2 by the control device 36 and translated bythe trolley 13 activated by the motor 18.

According to the embodiment shown, the ribbon 2 of rubber-coated fabricis supported upstream and downstream of the cutting direction C-C by thecounter-blade 7 cooperating with the punching disc 9 for obtaining saidnotch 24. According to said embodiment, although the ribbon 2 ofrubber-coated fabric is supported by said counter-blade 7, the portionof ribbon astride the cutting direction C-C at the working position W(said portion being indicated at F in FIG. 4) can still freely shift ina direction parallel to the lying plane of said ribbon. In other words,the cords 3 incorporated in the portion F of the ribbon 2 can move awayfrom the punching device 4 in a direction substantially perpendicular tothe cutting direction C-C.

In the preferred embodiment shown in FIG. 4, the notch 24 is athrough-notch: however, according to further embodiments not shown, thestep of forming the notch may concern a prevailing portion of thethickness of the ribbon 2 of rubber-coated fabric, leaving under thenotch a thin layer of elastomeric material having a thickness such asnot to interfere with the subsequent introduction of the cutting blade19 through said notch.

According to the preferred embodiment shown in FIG. 4, the notch 24 isformed astride the central longitudinal plane Π-Π of the ribbon 2. Inthis way, the central portion is advantageously selected as firstportion of the ribbon 2 to be cut, said central portion being lesssubjected to strains which could cause an accidental deviation of theinclination of the reinforcing cords 3 with respect to the nominalinclination.

In a subsequent step of the method, the counter-blade 7 of the punchingdevice 4 is moved away from the working position W—in the case in point,lowered—by the stem 31 of the pneumatic cylinder 23 to a position ofnon-interference with the cutting device 5.

According to the preferred embodiment shown, the ribbon 2 ofrubber-coated fabric is supported downstream of the cutting directionC-C by the sheet 30, while being still free to shift the portion F ofthe ribbon 2 in a direction parallel to the lying plane of the ribbon 2,thus allowing the cords 31 to correspondingly shift in a directionsubstantially perpendicular to the cutting direction C-C, so as toprevent damages or accidental cuts of the cords 3.

After having lifted the punching disc 9 away from the ribbon 2 ofrubber-coated fabric by means of the control device 36 or simultaneouslywith such lifting step, in a further step of the method of theinvention, as shown in FIGS. 5 and 6, the cutting blade 19 is insertedthrough the notch 24 by the control device 37, in such a way as to passover the lying plane of the ribbon 2 supported by the sheet 30.

At this point, as shown in FIGS. 7 and 8, a first cut of the ribbon 2 isperformed by shifting the blade 19 along the cutting direction C-C bymeans of the trolley 13 for a first portion extending between the notch24 and a first lateral edge 25 of the ribbon 2 and, at the end of saidstep (as shown in FIGS. 9 and 10), a second cut of the ribbon 2 isperformed by shifting the blade 19 by means of the trolley 13 along thecutting direction C-C for a second portion extending between the notch24 and an opposite lateral edge 26 of the ribbon 2.

Preferably, the first cutting step is carried out limiting the stroke ofthe trolley 13, so as to hold the cutting blade 19 within the lateraledge 25 of the ribbon 2. In this way, the cutting blade is convenientlyheld within the cords 3 and the start of the second cutting step isfacilitated, as this step does not require to position again the cuttingblade 19 within the cords 3.

More in detail, according to said embodiment, once the first cut of theribbon 2 has been performed, the blade 19 is moved by the trolley 13towards the notch 24, making backwards the path followed during saidfirst cut and remaining therefore within the groove obtained during saidfirst cut. Subsequently, once the notch 24 has been reached, saidcutting blade 19 is moved towards the opposite edge of said ribbon, soas to perform said second cut of said ribbon.

According to a further embodiment, once said first cut of the ribbon 2has been performed, the blade 19 is lifted and makes backwards, towardsthe notch 24, the path followed during said first cut remaining inlifted position, i.e. without interacting with said ribbon.Subsequently, once said notch 24 has been reached, the blade 19 islowered and moved towards the opposite edge of the ribbon so as toperform the second cut of the same.

According to a preferred embodiment of the invention, the cutting blade19 is heated to a given temperature, so as to facilitate the cuttingoperations of the portion of rubber of the ribbon 2 interposed betweenadjacent cords.

A man skilled in the art may introduce in the above described inventionmodifications and variants in order to fulfill specific and contingentapplicative requirements, modifications and variants anyhow fallingwithin the protection scope as defined by the subsequent claims. Asshown in FIG. 11, for example, it is possible to provide a pair ofcutting blades 19, each of which is provided with its own cutting edge,said blades, once introduced into the notch 24, being separately movedon opposite parts of the cutting direction C-C, so as to execute at thesame time the first cut and the second cut of the ribbon ofrubber-coated fabric, with an advantageous increase in the productioncapacity of the method of the invention.

1. A method for cutting a ribbon of rubber-coated fabric, comprising:dragging a free end of the ribbon for a portion of predetermined lengthpast a working position of a punching device; forming a notch ofpredetermined length between two adjacent reinforcing cords of theribbon using the punching device; moving a counter-blade of the punchingdevice away from the working position; inserting at least one cuttingblade through the notch so that the at least one cutting blade passesover a lying plane of the ribbon; performing a first cut of the ribbonby shifting the at least one cutting blade along a cutting direction fora first portion extending between the notch and a first lateral edge ofthe ribbon; and performing a second cut of the ribbon by shifting the atleast one cutting blade along the cutting direction for a second portionextending between the notch and an opposite lateral edge of the ribbon;wherein the ribbon includes a plurality of the reinforcing cords,wherein the plurality of reinforcing cords are substantially parallel toone another, and wherein the notch extends along the cutting directionsubstantially parallel to the plurality of reinforcing cords.
 2. Themethod of claim 1, wherein forming the notch of predetermined length iscarried out by supporting the ribbon upstream and downstream of thecutting direction at a distance so as to allow freedom of shifting, in adirection parallel to the lying plane of the ribbon, of a portion of theribbon located at the working position of the punching device astridethe cutting direction.
 3. The method of claim 1, wherein the first andsecond cuts are carried out by supporting the ribbon upstream anddownstream of the cutting direction at a distance so as to allow freedomof shifting, in a direction parallel to the lying plane of the ribbon,of a portion of the ribbon located astride the cutting direction.
 4. Themethod of claim 1, wherein forming the notch of predetermined length iscarried out using a rotational-translational movement of an incisiontool of the punching device.
 5. The method of claim 1, wherein movingthe counter-blade and inserting the at least one cutting blade arecarried out simultaneously.
 6. The method of claim 1, wherein performingthe first cut and performing the second cut are carried outsimultaneously.
 7. The method of claim 1, further comprising moving thepunching device away from the working position before inserting the atleast one cutting blade through the notch.
 8. The method of claim 1,wherein the notch is formed astride a central longitudinal plane of theribbon.
 9. The method of claim 1, wherein performing the first cut iscarried out by holding the at least one cutting blade within oppositelateral edges of the ribbon.
 10. The method of claim 1, furthercomprising heating the at least one cutting blade to a giventemperature.